Generally speaking, this invention relates to a dispensing mechanism for containers, which mechanism also serves as a cap for the opening in the container. More particularly, this invention relates to a dispenser mechanism for squeeze-bottle type containers wherein a dual valve arrangement provides for dispensing of the contents of the container with an automatic closing function during periods of non-use. Thus, the material in the container is not exposed to ambient until such time as it is dispensed.
A valve opens under the action of pressure applied to the contents being expelled from the container as a result of the container being squeezed. During this operation, internal pressure overcomes the combined ambient pressure, and the pressure biasing the valve into closed position. Once the dispensing function has ceased, and pressure against the bottle or container wall is removed, pressure is reduced internally of the container and ambient pressure overcomes a second valve biased against the ambient pressure to cause air to flow through the dispensing path to remove any material left therein, and to force it back into the container. Simultaneously, this pressure overcomes the first dispensing valve to close it, and to seal against the valve seat. Subsequently, this return flow causes the pressure internally and externally of the container to equalize, and the second valves closes and seals off the container contents from ambient.
Thus, the dual valves of the invention herein respond to differences in pressure and cooperate to dispense the contents of the container, or to seal the contents thereof during non-use. The cap or closure of the invention may include a dispenser spout which is cleaned of material automatically at the end of the dispensing period by the differential pressure between ambient and internally of the container, causing the remainder of any dispensed material in the spout to be forced back into the container.
One of the important advantages to the arrangement of apparatus herein is its single-handed control of the materials being dispensed. That is, certain materials are hard to handle and control during dispensing, such as, for example, stains wherein it is important to dispense a certain quantity of stain, while promptly shutting the dispensing action without any further dripping or dispensing of small quantities from the dispenser opening. As will be appreciated, dripping stains can create certain problems if the material drops on other than the area where the material is being dispensed. Moreover, in certain applications, it is important that the environment where the material is being dispensed not be contaminated in any way by the application of the material being dispensed to an area other than the actual precise place where the material is to be applied.
Many prior art arrangements allow for a dispensing with a subsequent sealing action, but they require a two-handed arrangement wherein the closing action must be done by the operator's second hand from that which is actually causing the dispensing of the materials from the container. Or other arrangements simply require that each hand manipulate one of two parts to accomplish closing. Moreover, certain arrangements, while appropriate for dispensing materials, as required, cannot handle low viscosity solutions such as stain solutions, without leaking.
Certain other arrangements have been provided in the past wherein a dual valving system is utilized. One such arrangement is disclosed in U.S. Pat. No. 4,073,294. In that patent, a tandem arrangement of one-way spring-biased ball-check valves is disclosed. The arrangement is utilized to generated a vacuum in an attached container, and it operates to handle a gaseous substance rather than a powder or liquid. The arrangement is such that a vacuum is maintained when the system is at rest, as opposed to the arrangement herein where there is an equalization of pressure when the system is at rest.